Most valves, except the small sizes normally used in individual domestic water and gas supply installations, require some type of actuator. The use of an actuator may be necessary because the valve must be actuated by remote means or the force required to actuate the valve makes manual actuation very difficult or impossible. Also, the valve may be so located that access for manual operation is either difficult or not available.
Irrespective of the reason for use of an actuator, it is necessary to secure the actuator to the valve so that the torque generated by the actuator does not cause displacement between the actuator and the valve body. It is also necessary to prevent separation occurring between the valve and actuator. This is important because the torque transmitting linkage between the actuator and the valve must be of a type suitable only for transmitting torsional loads in order to facilitate mounting of the actuator on the valve. Thus, the mount itself must transmit the counterforces and positively prevent any tendency to separate as a result of vibration and shock resulting from the stopping and starting of the actuator. This requires the actuator to be firmly attached to the valve body by means adequate to positively transmit the torsional forces generated by the actuator. Although various actuator mounts have been developed, all of them have required the valve body to be provided with special lugs, flanges or bosses for mounting fasteners such as bolts or studs. Thus, the valve body has to be specifically designed to mount the actuator support. The result was to require each actuator mount to be custom designed for the particular make, size and design of valve with the attendant design and manufacturing costs and limitations on availability. Also a broken lug or flange or a damaged thread on either the support or the valve body often resulted in costly and frustrating delays in restoring the valve to service.